Distribution of galanin‐like immunoreactivity in the brain of Rana esculenta and Xenopus laevis

Abstract

The immunocytochemical distribution of galanin-containing perikarya and nerve terminals in the brain of Rana esculenta and Xenopus laevis was determined with antisera directed toward either porcine or rat galanin. The pattern of galanin-like immunoreactivity appeared to be identical with antisera directed toward either target antigen. The distribution of galanin-like immunoreactivity was similar in Rana esculenta and Xenopus laevis except for the absence of a distinct laminar distribution of immunoreactivity in the optic tectum of Xenopus laevis. Galanin-containing perikarya were located in all major subdivisions of the brain except the metencephalon. In the telencephalon, immunoreactive perikarya were detected in the pars medialis of the amygdala and the preoptic area. In the diencephalon, immunoreactive perikarya were detected in the caudal half of the suprachiasmatic nucleus, the nucleus of the periventricular organ, the ventral hypothalamus, and the median eminence. In the mesencephalon, immunoreactive perikarya were detected near the midline of the rostroventral tegmentum, in the torus semicircularis and, occasionally, in lamina A and layer 6 of the optic tectum. In the myelencephalon, labelled perikarya were detected only in the caudal half of the nucleus of the solitary tract. Immunoreactive nerve fibers of varying density were observed in all subdivisions of the brain with the densest accumulations of fibers occurring in the pars lateralis of the amygdala and the preoptic area. Dense accumulations of nerve fibers were also found in the lateral septum, the medial forebrain bundle, the periventricular region of the diencephalon, the ventral hypothalamus, the median eminence, the mesencephalic central gray, the laminar nucleus of the torus semicircularis, several laminae of the optic tectum, the interpeduncular nucleus, the isthmic nucleus, the central gray of the rhombencephalon, and the dorsolateral caudal medulla. The extensive system of galanin-containing perikarya and nerve fibers in the brain of representatives of two families of anurans showed many similarities to the distribution of galanin-containing perikarya and nerve fibers previously described for the mammalian brain.

Immunohistochemical localization of cocaine‐ and amphetamine‐regulated transcript peptide in the central nervous system of the frog Rana esculenta

“…The location of orexogenic peptides in the anuran brain is also similar to that in the mammalian brain. Galanin-like (Lázá r et al, 1991;Olivereau and Olivereau, 1992), neuropeptide-Y-like (Danger et al, 1985;Lázár et al, 1993), and orexin-like (Galas et al, 2001) immunoreactive cells and fibers were located in the preoptic area, the magnocellular preoptic nucleus, and the ventral hypothalamus. Cells showing melanin concentrating hormonelike immunoreactivity in the frog brain were restricted to the posterior tubercle, periventricular organ, and the dorsal hypothalamic nucleus .…”

“…The nomenclature used to designate nuclei and pathways in the frog brain was mostly according to Lázá r et al (1991), whereas some structures in the telencephalon were named according to Marín et al (1998).…”

Immunohistochemical localization and biochemical characterization of hypocretin/orexin-related peptides in the central nervous system of the frogRana ridibunda

“…All these hypothalamic nuclei contain neuroendocrine neurons that project to the median eminence and the neurointermediate lobe of the pituitary (Neary and Northcutt 1983;Tuinhof et al, 1994). In frog, some of these neurons express various hypophysiotropic neuropeptides such as corticotropin-releasing factor , thyrotropin-releasing hormone (Lamacz et al, 1989), somatostatin (Laquerrière et al, 1989), growth hormonereleasing hormone (Marivoët et al, 1988), gonadotropinreleasing hormone (Andersen et al, 1988;Collin et al, 1995), pituitary adenylate cyclase-activating polypeptide (Yon et al, 1992), ␣-melanocyte-stimulating hormone (Benyamina et al, 1986), melanin-concentrating hormone (Andersen et al, 1986), neuropeptide Y (Danger et al, 1985), enkephalins (Merchenthaler et al, 1989), calcitonin gene-related peptide (Mulatero and Fasolo, 1991), and galanin (Lázá r et al, 1991). That hcrt-immunoreactive fibers were not detected in the frog median eminence suggests that hcrts do not directly regulate the activity of adenohypophysial cells.…”

Peptides in frog brain areas processing visual information

“…The distribution of these peptides was described only in the tectum in the literature covered by this review. We found earlier (Lázá r et al, 1991;Merchenthaler et al, 1989) that ENK-and GAL-ir nerve fibers showed a characteristic complementary arrangement in the npB and Cg. Since the other peptides discussed in this review are poorly represented in the LGC, I illustrate enkephalin and GAL immunoreactivity in photomicrographs from my collection.…”

“…In R. esculenta, a loose network of thick ir-fibers was found in lamina G and the inner half of layer 8. Dot-like fiber particles occurred in lamina B and D, while in layers 6 to 3 loosely arranged ir-fibers could be stained (Lázá r et al, 1991) (Figs. 2E, 5B,D, 6).…”